feat: enhance collaboration guidelines in documentation and refactor mention handling for improved clarity and functionality

backend/tests/test_mentions.py

@@ -0,0 +1,20 @@
+from app.models.agents import Agent
+from app.services.mentions import extract_mentions, matches_agent_mention
+
+
+def test_extract_mentions_parses_tokens():
+    assert extract_mentions("hi @Alex and @bob-2") == {"alex", "bob-2"}
+
+
+def test_matches_agent_mention_matches_first_name():
+    agent = Agent(name="Alice Cooper")
+    assert matches_agent_mention(agent, {"alice"}) is True
+    assert matches_agent_mention(agent, {"cooper"}) is False
+
+
+def test_matches_agent_mention_supports_reserved_lead_shortcut():
+    lead = Agent(name="Riya", is_board_lead=True)
+    other = Agent(name="Lead", is_board_lead=False)
+    assert matches_agent_mention(lead, {"lead"}) is True
+    assert matches_agent_mention(other, {"lead"}) is False
+